配网单相接地故障消弧及定位的研究

发布时间：2019-03-13 17:12

【摘要】：随着电网的日益复杂,当其出现单相接地故障时,产生的电弧和对人身安全造成的危害愈来愈严重,因此提高配网供电的安全可靠性非常紧迫,而关键就是研究配网系统的消弧、选线与定位。本论文首先对配网系统及其单相接地故障后的消弧选线定位进行了简单介绍,然后通过对消弧原理的分析,提出配网母线主动快速接地消弧技术,当配网发生单相短路故障时,通过快速开关准确快速地将接地网以及接地相完全的重复接地,以此达到消弧的目的,并给出了具体装置的接线图,通过MATLAB仿真验证该消弧方法的可以实现快速消弧,防止过电压危害。选线部分先简要介绍了故障选线的能量函数值法,为了提高选线精确度,提出了能量函数值法和小波分析法相结合的选线策略。非故障线路和故障线路能量函数值的正负及其零序电流小波分解后的波形幅值和相位都有明显不同。利用MATLAB进行仿真建模,经大量的实验结果表明,本文提出能量函数值法和小波分析结合选线的方法是有效准确快速的,不受过渡电阻、故障距离以及相位的影响。通过上述选线方法找到故障线路后,还需对故障位置进行判断。本文提出了配网不接地系统电缆均匀线路单相接地故障时的定位方法,在中性点加快速开关将系统转变为易于研究的大电流接地系统,假设单相接地过渡电阻为纯电阻性的,进一步假设零序电流分配系数为实数,推导出求解故障距离的方法。利用MATLAB软件仿真了算法在线路不同地点,经不同过渡电阻接地故障的定位准确性。仿真结果表明在不同过渡电阻,故障距离条件下,定位结果精度都很高。
[Abstract]:With the increasing complexity of the power grid, when the single-phase grounding fault occurs, the arc generated and the harm to the personal safety become more and more serious, so it is very urgent to improve the safety and reliability of the distribution network power supply. And the key is to study the arc suppression, line selection and location of the distribution network system. In this paper, the distribution network system and the location of arc suppression line after single-phase grounding fault are introduced briefly. Then through the analysis of arc suppression principle, the active fast grounding arc suppression technology of distribution network bus is put forward. When the single-phase short circuit fault occurs in the distribution network, the technology of arc suppression is put forward. In order to achieve the goal of arc suppression, the grounding grid and grounding phase are grounded exactly and rapidly by the fast switch, and the wiring diagram of the specific device is given. The simulation results of MATLAB show that the arc suppression method can achieve rapid arc suppression. Prevent over-voltage damage. In the section of line selection, the energy function method of fault line selection is introduced briefly. In order to improve the accuracy of line selection, a line selection strategy combining energy function method and wavelet analysis method is proposed. The positive and negative values of the energy function between the non-fault line and the amplitude and phase of the waveform after wavelet decomposition of the zero sequence current are obviously different between the non-fault line and the fault line. Simulation modeling with MATLAB is carried out. A large number of experimental results show that the proposed method combined with energy function method and wavelet analysis is effective, accurate and fast, and is not affected by transition resistance, fault distance and phase. After the fault line is found by the line selection method, the fault location should be judged. In this paper, a locating method for single-phase grounding fault of uniform cable line in power distribution system without grounding is presented. The system is transformed into a large current grounding system which is easy to be studied by adding a fast switch at the neutral point, assuming that the transition resistance of single-phase earthing is pure resistive. Furthermore, assuming that the distribution coefficient of zero sequence current is a real number, the method to solve the fault distance is derived. MATLAB software is used to simulate the location accuracy of grounding fault with different transition resistances in different locations of the line. The simulation results show that the accuracy of location results is very high under different transition resistance and fault distance.
【学位授予单位】：华北电力大学(北京)
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TM862

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